Typically, large numbers of mass spectrometer targets, in particular Matrix-Assisted Laser Desorption/Ionization (MALDI) mass spectrometer targets, are difficult to process in a single batch. The batch size is often limited by the number of targets that can be applied in rows and columns on a sample plate. A small batch size requires frequent opening and closing of the mass spectrometer vacuum chamber, thereby slowing the overall analysis process. Additionally, small batch sizes may create difficulties in performing MALDI mass spectrometric analysis on the entire effluent of a capillary chromatographic assay. The small batch sizes normally require that only intermittent sample portions of the effluent be subjected to mass spectrometric examination.
A typical sample substrate used in mass spectrometric analysis consists of a metal plate. Processing large batch sizes of samples using traditional MALDI metal plate substrates may be expensive due to the relative high cost of the MALDI metal plate substrates. Additionally, the archiving of samples that have been subjected to MALDI mass spectrometric analysis using traditional metal plate substrates may be costly due to the decreased future usefulness and the required metal plate substrates. Large volume substrates may reduce the cost inherent in processing large batch sizes of samples. However, large volume substrates present their own set of challenges such as the control of outgassing when the substrate is first subjected to a vacuum. In particular, the generally larger surface area of large volume substrates may outgass more than smaller substrates. Excessive outgassing may adversely affect the MALDI mass spectrometric analysis. Accordingly, an apparatus and method that supports the spectrometric analysis of large batch sizes is desirable.